Steam-engine



P. A-.GRESSWE'LL "STBAM'ENGINL F'Jatented Feb. 14, 1888.

(A .(1ttorney.

WITNESSES Y l y 4Q/. mm1 y .f f- Mw? UNITED STATES PATENT OFFICEQ FRANcis A. oREsswELL, or sTRoNesrowN, PENNSYLVANIA.

" STEAM-ENGINE.-

sPncgIrIcA'rroN forming pari; of nemers Patent No. 378,041, dated February 14, laas. Application filed April 11, 1887. Serial No. 234,376. (No model.)

To aZ Z whom, it mag/concern:

Be .1t known that I, FRANCIS A; CREssWELL, a citizen of the United States, residing at Strongstowmin the county of Indiana and State of Pennsylvania, have invented certain new and useful' Improvements in Steam-Engines; and I do declare the following to be a full,clear, and exact description ofthe invention, such as will enable others skilled in the art to which it lappertains to make and use the same, referthe usual crank yand pitman mechanism thatv will produce no dead-points. These objects I accomplish by the construction and novel ar-r rangement of parts hereinafter described, and embraced in the appended claims.

Referring to the accompanying drawings by letter, A designates the cylinder, closed at both ends, but'open at a on its side opposite the steam-chest.

B are two similar pistons reciprocatingin theslmllar complete end portions, a a', of the cylinder and secured to the ends of a pistonrod, b, a suitable distance shorter than the cylinder from head to head, and provided with a rack, b', on the side opposite the steam-chest.

OC are twosiinilar shafts passing through the space ciin the cylinder, and provided on one slde of the latter with the equal-sized intermeshing gear-wheels c c.

D D are equal-sized segmental gears secured, respectively, on the shafts C C and arranged to mesh alternately with the rack b', one becoming engaged therewith j ust before the other disengages. As the piston-rod moves in one direction, the rack b engages the segmental gear D and rotates the shaft C,which,by means of the intermeshing gears c c', rotates the shaft C in the opposite direction. When the piston-rod reverses its reciprocation, the gear D disengages from the rack b', and the gearD engages therewith and is moved thereby in A the direction opposite to that of the gear D, so that they opposite rotations of the shafts C C are kept up continuously.y On either shaft is secured a pulley, d, which can be belted to apulley on any machine it is'desired to operate.

The steam is admitted to the closed ends a'v a of the cylinder behind the pistons B B by the following means:

E is the steam-chest, and e e are the steamports having the orifices e e at the ends of the cylinder, and the orifices e2 e2 yentering the steam-chest, between which latter orifices lis the exhaust-port es. The steam-chest is provided with the entrance-port F from the steampipe, and has forming part of it the valvecylinder G, provided with the two portsg g', a suitable distance apart, cut transversely through it for a little more thanlnalf its diameter, and which register with the orifices e2 v e2 of the steam-ports e e.

H is a hollow piston-valve, closed at the ends, reciprocatingin the cylinder G, provided on one side with the steam-port H', cut transversely through it for a little more than half its diameter, and on the kopposite side with theLsimilar steamfports, h h', equally distant from the port H', toward the opposite ends of the cylinder G. Between the ports h' his the concave exhaust space. or chamber I, closed in so as to have no communication with the interior ofthe valve, and i' i are similar, but shorter, exhaust-spaces an equal distance on each side of the port H. Y

J J are steam-tubes which run voutward from the opposite ends of the valve-cylinder G,`the said tubes having coupling-pieces at the outer ends, connecting them, respectively, with the tubes K K', which ppen into the ends a a ofthe cylinder A, at equal distances fromthe head thereof, at the respective points 7c k'. l

vL is a straight rack-bar running through a suitable opening or groove, Z, on the side of the steam-chest and engaginga toothed por! tion, Z', of the peripheral surface of the valve. By means of the said portion andthe rack the valve is reversed; but as this .mechanism is shown' and described in a former patent granted toA me no broad claim is made to it in the present application.

The operation of the rack b', segmental gears,

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meshing gear-wheels, and shafts has been described.

The following is the opera-tion of the valve mechanism: In Fig. 1 the steam is passing within the hollow valve through the port g, and thence through the port H', which overlaps the port g, into the. corresponding steamport, e, whence it passes into one end portion a' of the cylinder A and drives the corresponding piston B inward. The piston-valve H is now adjacent to the steam-tube J, and the steam-port e on the opposite side communicates with the exhaust-port e through the exhaust-space i'. When the inwardly-moving piston B passes the orifice k, some of the steam behind it passes through the tube K and drives the corresponding end of the valve H inward, the opposite end of the cylinder G exhausting through the tube K' and orifice k', which is inward from the corresponding piston B and can communicate with the open air through the space a. The steam from the tube K moves the valve till the port H registers with the port g', and the exhaust-space t' conneet-s the corresponding steam-port, e, with the exhaust-port The movement of the pistons B B is then reversed. Each orice k 7c' is so situated as to admity steam to the corresponding tube, K or K, and turns to move the valve before the opposite piston B has reached the end of its stroke, so that the corresponding end, a., of the cylinder takes steam and cushions said piston. To reverse the engine, the piston-valve H is 'one-half rotated by means of the rack and toothed portion of said valve. Then, if the ports are in position shown in Fig. l, the port h' will open into the orifice e2 of the steamport e, with which it registers, and the exhaust-space I will connect the opposite steam-port, e, with the exhaust-port ai', so that the iiow of steam, as indicated by arrows in the said figure, will be reversed.

Having described my invention, I claiml. The combination of the main cylinder open centrally on one side, the similar pistons moving in the complete ends of said cylinder, the piston-rod connecting said pistons and having a rack formed upon it, the similar shafts provided with equal-sized intermeshing gear-wheels, the similar segmental gears secured to their respective shafts in such positions that one engages with the rack on the piston-rod as the other disengages therewith,

and that the said change of engagement occurs at the end of each stroke of the pistons, substantially as specified.

2. The combination, with the main cylinder lhaving the steam-ports e e and exhaustport e, the two similar pistons and the rod connecting the latter, of the steam-chest having the steam-ports g g' in its cylindrical portion, the hollow piston-valve provided with the port H' and exhaust-spaces i i', and the steam-tubes J J'and K K', respectively opening into the cylinder at the points k k', substantially as specified.

3. The combination, with the main cylinder having the steam-ports e e and exhaust-port e3, the two pistons and connecting piston-rod of the steam-chest having the ports g g' in its cylinder, the piston-valve provided with the steam-ports H', h, and h', and exhaust-spaces I, 13, and i', the tubes J J'and K K', opening into the main cylinder at the points k k',and mechanism, substantially as described, to half rotate the piston-cylinder.

4, The combination, with the main cylinder having the steam-ports e e and exhaust-port e", and the two pistons and connecting piston-rod, ofthe steam-chesthaving the steam-ports g gon its cylinder G, the piston-valve provided with the steam-ports H', h, and h', and exhaustspaces I, t', and i', the steam-tubes J J' and K K', the toothed portion Lof the piston-valve, and the straight rack-bar l, engaging there with, substantially as specified.

5. The combination, with the main cylinder having the open part a, complete end parts, a', steam-ports e e and exhaust-port e, the two pistons B, and piston-rod b, having therack b formed upon it, the twoshafts CO', connecting the intermeshinggear-wheels c c', and the segmental gearsD D',secured, respectively, in said shafts, of the steam-chest provided with the steam-ports g g on its cylinder G, the pistonvalve provided with the port H' and steamspaces i i', and the steam-tubes J J and K K', opening into the end ports, a', of the main cylinder at the points k 7c', substantially as specified.

In testimony whereof I affix my signature in presence of two witnesses.

FRANCIS VA. CRESS\VELL Vitnesses:

J. W. CLARK, S. J. TELFORD. 

